Grate the carrot with a box grater.

Chop the green onions.

Finely chop or crush the garlic cloves.

Gently separate the spring roll wrappers so they are ready to use.

Add the ground pork, grated carrot, green onions, garlic, oyster sauce, soy sauce, chicken bouillon powder or MSG, black pepper, and egg to a medium mixing bowl.

Add the toasted sesame oil and water chestnuts if using.

Mix vigorously with a fork or clean hands until the filling becomes sticky and fully combined.

Lay one spring roll wrapper flat on your board like a diamond.

Place about 1 tbsp of filling near the bottom point of the wrapper.

Shape the filling into a thin horizontal log.

Fold the bottom point over the filling.

Fold the left and right points toward the center.

Roll tightly toward the top point.

Dip your finger in water and wet the top point of the wrapper.

Press the wrapper closed to seal.

Repeat until all wrappers and filling are used.

Place a large frying pan over medium heat and add the cooking oil.

Heat the oil for 3–4 minutes.

Test the oil by dropping in a small torn piece of wrapper. If it bubbles immediately, the oil is ready.

Carefully place the lumpia in the hot oil without overcrowding the pan.

Fry for 5–6 minutes, turning occasionally with tongs, until golden brown and crisp on all sides.

Transfer the cooked lumpia to a paper towel-lined plate.

Serve hot with sweet chili sauce, banana ketchup, or vinegar dipping sauce.